Mahouts and their elephants display a poster during a campaign ahead of the August 7 referendum in Auytthaya province, north of Bangkok, Thailand, August 1, 2016. Officials across the country are drumming up campaigns to encourage voting on the draft constitution in a referendum on Sunday. (Photo by Chaiwat Subprasom/Reuters)

Puerto Rico's Grace Claxton warms up before competing in the Women's 400m Hurdles Round 1 during the athletics event at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 15, 2016. (Photo by Jewel Samad/AFP Photo)

A mock-up of a typical British suburban home is seen sinking into the River Thames, in a protest by Extinction Rebellion to demand faster government action on climate change in London, Britain on November 10, 2019. (Photo by Extinction Rebellion/Handout via Reuters)

A rider rears up on his horse while surrounded by a cheering crowd during the traditional Fiesta of San Joan (Saint John) in downtown Ciutadella, on the Spanish Balearic Island of Menorca, June 23, 2014. The riders of the horses are representatives of ancient Ciutadella society – nobility, clergy, craftsmen and farmers. (Photo by Enrique Calvo/Reuters)

A forest near Chatillion, a small village in Belgium, used to be home to a vintage car graveyard. This “car graveyard” has since been cleaned up, but photographer Theo van Vliet had the chance to explore the forest and photograph the cars beforehand. (Photo by Theo van Vliet)

2000 attended a welcome party at TigerTiger Manchester which was the first event in set of big club night for new students to Manchester and Salford universities in Manchester, UK on September 19, 2016. This year, university bosses have stepped up security in Manchester. (Photo by Jordan Sinclair/UK News Pictures)

A newly born Sitatunga calf seen at ZSL Whipsnade Zoo on November 24, 2016 in Whipsnade, England. The swamp-dwelling species, also known as a marshbuck, is Africa's only true amphibious antelope. It was snuggled up in the leaves and almost perfectly camouflaged as it mother tended it. (Photo by Tony Margiocchi/Barcroft Images)

A dressed up participant without trousers takes part in the 2017 No Pants Subway Ride in New York, the United States, on January 8, 2017. The event, which first took place in New York in 2002, has become a yearly event attended by people in more than 60 cities across the globe. (Photo by Zou Zheng/Xinhua/Sipa USA)